Rank Math Compatibility Solution Fix

Below is a complete, copy-paste friendly solution you can post on the plugin forum. It explains the cause + gives the exact fix and rollback steps. ✅ Fix: Rank Math update causes fatal error in CF Images (MyThemeShop\Helpers\Str not found) Symptoms / Error

After updating Rank Math, the site starts throwing a fatal error like:

PHP Fatal error: Uncaught Error: Class "MyThemeShop\Helpers\Str" not found .../wp-content/plugins/cf-images/app/integrations/class-rank-math.php on line 229 Why it happens

The CF Images plugin has a Rank Math integration that still calls the old Rank Math / MyThemeShop namespace:

• MyThemeShop\Helpers\Str

Newer Rank Math versions no longer provide that class under the MyThemeShop namespace, so CF Images crashes when it tries to use it. ✅ Quick Recovery (optional)

If your site is down and you need it back immediately:

• Deactivate CF Images from WP Admin, or
• Rename the folder:

/wp-content/plugins/cf-images → /wp-content/plugins/cf-images.disabled

Once the site is back, apply the permanent fix below. ✅ Permanent Workaround (no core plugin edits): MU-Plugin Shim

This solution keeps Rank Math + CF Images working without editing plugin files, so it won’t get overwritten by updates. Step 1 — Create the MU-Plugins folder (if needed)

Create this folder:

/wp-content/mu-plugins/ Step 2 — Create a shim file

Create this file:

/wp-content/mu-plugins/rankmath-mythemeshop-shim.php Step 3 — Paste this code inside

<?php /** * Rank Math compatibility shim for plugins still referencing MyThemeShop namespace. * * Fixes fatal: Class "MyThemeShop\Helpers\Str" not found * Caused by CF Images calling the old class after Rank Math namespace changes. */ add_action('plugins_loaded', function () { // If the old class is missing but the new Rank Math class exists, alias it. if ( ! class_exists('MyThemeShop\\Helpers\\Str') && class_exists('RankMath\\Helpers\\Str') ) { class_alias('RankMath\\Helpers\\Str', 'MyThemeShop\\Helpers\\Str'); } }, 20); Step 4 — Refresh the site

The fatal error should be gone immediately.